Filter device, in particular for gas filtration

ABSTRACT

A filter device with filter housing and housing cover has a filter element disposed therein. A first holding part on the filter element projects past an outer wall surface of the filter element. A second holding part in the form of a counter holding part on the housing cover interacts with the first holding part. The first and second holding parts engage each other in a mounted state of the filter element. A first form-fit part is arranged on the filter element axially spaced from the first holding part and is associated with a second form-fit part in the form of a counter form-fit part. The first form-fit part and the first holding part, by rotational movement of the filter element about a longitudinal axis of the filter element, are each transferable into a form-fit engaged state with the counter holding part and the counter form-fit part, respectively.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of internationalapplication No. PCT/EP2013/067424 having an international filing date of22 Aug. 2013 and designating the United States, the InternationalApplication claiming a priority date of 22 Aug. 2012, based on priorfiled German patent application No. 20 2012 012 669.5, and furtherclaiming a priority date of 22 Aug. 2012, based on prior filed Germanpatent application No. 10 2012 016 557.9, the entire contents of theaforesaid international application and the aforesaid two German patentapplications being incorporated herein by reference.

BACKGROUND OF THE INVENTION

The invention concerns a filter device, in particular for gasfiltration, for example, an air filter for internal combustion engines,comprising a filter element that is received in a filter housing whichis closable by a housing cover, wherein on the filter element a holdingpart is arranged that projects past the outer wall surface and hascorrelated therewith a counter holding part on the housing cover and theholding parts engage each other in the mounted state. The inventionconcerns also a filter element receivable in the filter device.

Air filters for motor vehicles for filtration of the combustion air tobe supplied to an internal combustion engine of a vehicle are known.Such an air filter as described, for example, in DE 20 2005 020 099 U1,comprises a hollow-cylindrical filter element which is flowed throughradially from the exterior to the interior by the combustion air to bepurified, wherein the clean air is discharged axially. The filterelement is received in a filter housing and, according to DE 20 2005 020099 U1, is secured by a clamping and locking action on a counter holderon the inner side of the housing cover by means of a holding part, whichis formed monolithically with an end-face end disk of the filter elementand is projecting radially past the wall surface of the filter element.In this context, the holding part during the insertion movement of thefilter element is axially locked with the counter holder.

Comparable embodiments are also disclosed in WO 2011/104107 A1, DE 102011 120 073 B3, and U.S. Pat. No. 7,604,677 B2.

SUMMARY OF THE INVENTION

The invention has the object to configure a filter device with simpleconstructive measures such that the filter element is securely held andcan be exchanged in a simple way.

This object is solved according to the invention in that on the filterelement, at an axial spacing to the holding part, a form-fit part isarranged that has correlated therewith a counter form-fit part, whereinthe form-fit part and holding part by means of a rotational movementabout the longitudinal axis of the filter element are transferable intoa form-fit engaged state. The dependent claims provide expedient furtherembodiments.

The filter device according to the invention is used for filtration of afluid, in particular a gas, wherein optionally also liquid media can befiltered. Preferably, the filter device according to the invention isused as an air filter for motor vehicles, in particular for an internalcombustion engine or for the fresh air to be supplied to the interior ofthe motor vehicle.

In the mounted state, the filter element received in the filter deviceis secured on at least one location on the filter housing cover. Asecond location is provided either on the filter housing or also on thefilter housing cover.

In one embodiment with a fixation of the filter element exclusively inthe housing cover, tolerances and relative movements between housing andcover can be disregarded when designing the element fixation so that anarrower tolerance configuration of the connecting devices and thesealing device between filter element and housing cover is possible. Ina service situation, the filter element, held within the cover, can beremoved from the housing in a simple way. Removal of the filter elementfrom the cover is possible in a simple way outside of the installationenvironment of the air filter device.

The filter device comprises a filter element that can be flowed throughby the fluid to be purified and is received in a filter housing whichcan be closed off by a housing cover. On the filter element, a holdingpart is arranged that projects past the outer wall surface of the filterelement and has correlated therewith a counter holding part on thehousing cover. In the mounted state, the holding parts on the filterelement and on the housing cover engage each other so that a firstholding or fixation point for holding the filter element on the housingcover is provided.

Moreover, the filter element comprises a further connecting locationrelative to the housing or the housing cover. This is realized by meansof a form-fit part that is arranged with axial spacing relative to theholding part on the filter element and has correlated therewith acounter form-fit part. The counter form-fit part is located preferablyon the housing cover wherein optionally also an arrangement of thecounter form-fit part on the filter housing is conceivable. As a resultof the axial spacing between the holding part and the form-fit part thatare both arranged on the filter element, the filter element is securedby two different axially spaced apart connecting locations on thehousing or on the housing cover.

For holding and locking the filter element on the housing cover orfilter housing, a rotational movement about its longitudinal axis isimparted onto the filter element. The rotational movement of the filterelement transfers the holding part as well as the form-fit part on thefilter element into the locking position in which both parts areform-fittingly engaging the correlated counter holding part or counterform-fit part provided on the housing or on the cover. The form fit onthe holding part as well as on the form-fit part is thus produced by thesame rotational movement about the longitudinal axis of the filterelement. In a corresponding way, form fit for removal of the filterelement from the housing cover or filter housing can be canceled againby a rotational movement in the opposite direction.

The filter element is preferably embodied to be hollow-cylindrical andis flowed through radially from the exterior to the interior by thefluid to be purified. The externally positioned wall surface forms theraw side, the interior the clean side from which the purified fluid isdischarged axially. For insertion and mounting, the filter element ismoved axially into its mounting position and subsequently rotated aboutits longitudinal axis so far that the holding part and the form-fit parton the filter element move into form-fit position with the correlatedcounter holding part or counter form-fit part on the housing cover orfilter housing. In this connection, it may be expedient to embody atleast one of the locking devices like a bayonet closure in which, duringthe rotational movement, parts on the filter element and on the housingcover or filter housing lock form-fittingly with each other in such away that form fit is provided in axial direction. For example, theform-fit part on the filter element can be designed as a bayonetclosure. It is however also possible, additionally or alternatively, tolock the holding part like a bayonet closure on the housing cover orfilter housing.

According to a further expedient embodiment, the filter element on atleast one axial end face, optionally on both axial end faces, isprovided with an end disk, respectively, that is comprised, for example,of plastic material and is connected fixedly with the filter medium ofthe filter element. The end disks can be supports of the holding partand/or of the form-fit part on the filter element; optionally, theholding part and/or form-fit part is formed monolithically with therespective end disk. In this context, the holding part projects radiallypast the wall surface of the filter element while the form-pit part doesnot mandatorily project radially past the wall surface of the filterelement but optionally is positioned within the wall surface andprojects only in axial direction past the surface of the end disk. Theform-fit part is, for example, designed as a pocket which optionally isarranged at the axial end face of the end disk wherein the counterform-fit part on the housing or the cover is provided with a lockingelement that upon rotational movement of the filter element moves intothe pocket. The counter form-fit part has for this purpose a contourthat is complementarily embodied to the pocket on the filter element andthat moves circumferentially into the pocket that is open at one end,wherein the rotational movement is limited in that the counter form-fitpart impacts on the inner wall at the other end of the pocket.

Alternatively, the form-fit part can be embodied on an end disk as acontour, for example, in the form of hooks, which complementarilyengages counter form-fit parts that are designed as pockets.

The holding part on the filter element can be formed as a locking hookwhich is projecting radially past the filter element and in the mountedposition projects into a locking tab which forms the counter holdingelement on the housing cover. In this context, it can be expedient that,on the locking hook, at least one elastic springy contact part is formedthat in the mounted state loads the locking tab on the housing coverwith a clamping force so that the locking hook is held securely at thelocking tab. The elastic springy contact part is in particular formedmonolithic with the locking hook. In an alternative embodiment, theholding part on the filter element can be designed as a locking tabwhile a locking hook is embodied on the housing or housing cover.

In order to prevent accidental release of the filter element by returnrotation about the longitudinal axis of the filter element, according toa further advantageous embodiment an elastic snap lever is provided atthe housing or the cover which is resting in the mounted state on alocking projection at the circumferential side of the filter element.The snap lever can be arranged on the inner side of the housing cover oroptionally also immediately on the filter housing. The snap lever whichis advantageously formed monolithic with the housing cover or the filterhousing acts elastically in radial direction and projects with aclamping force radially into the locking projection on thecircumferential side of the filter element. In the mounted state arelease of the filter element is precluded in this way. The latter canbe removed only once the snap lever has been manually bent openelastically so that the snap lever is disengaged from the lockingprojection on the circumferential side of the filter element and thefilter element can be rotated back so far about its longitudinal axisthat the form fit between holding part and counter holding part as wellas between form-fit part and counter form-fit part is canceled;subsequently, the filter element can be removed axially.

In an alternative embodiment, an elastic snap lever is provided on theend disk which in the mounted state locks at a locking projection on theinner side of the housing cover or of the housing. The snap lever whichis advantageously formed monolithic with the end disk acts elasticallyin radial direction and projects with a clamping force radially into thelocking projection on the housing wall or the housing cover wall.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages and expedient embodiments can be taken from theadditional claims, the figure description and the drawings.

FIG. 1a shows in a perspective individual illustration an air filterhousing for an internal combustion engine of a vehicle.

FIG. 1b shows in a perspective illustration a horizontal section of anair filter with a hollow-cylindrical filter element that is secured withform fit on the filter housing cover (illustrated only partially).

FIG. 2 shows in an enlarged illustration a holding part on the filterelement which is embodied as a locking hook and is projecting into alocking tab on the inner side of the housing cover.

FIG. 3 shows the filter element in perspective view looking onto theclosed end disk.

FIG. 4 shows the filter element in perspective view looking onto the enddisk with clean air outlet.

FIG. 5 shows the filter element in a side view.

FIG. 6 is an enlarged illustration of a form-fit part that is embodiedas a pocket on one of the end faces of the filter element.

FIG. 7 is a perspective individual illustration of the housing cover.

FIG. 8 shows in an enlarged illustration a counter form-fit part on theinner side of the housing cover.

FIG. 9 shows the housing cover with inserted filter element in thelocked state.

FIG. 10 shows in an enlarged view a snap hook which is formed monolithicwith the housing cover, wherein the snap hook is resting on a lockingprojection at the circumferential side of the filter element.

FIG. 11 is an illustration in accordance with FIG. 9 but with the filterelement in the released state.

FIG. 12 is an illustration according to FIG. 10 with the snap hook inthe open state.

In the Figures, same components are provided with same referencecharacters.

DESCRIPTION OF PREFERRED EMBODIMENTS

In the Figures, an air filter for the internal combustion engine of amotor vehicle is illustrated as an embodiment. The filter device 1embodied as an air filter comprises a hollow-cylindrical filter element4 in a filter housing 2 (FIG. 1a ) which is flowed through by the fluidto be purified radially from the exterior to the interior. The air to bepurified flows through a lateral inlet E into the air filter housing 2.The discharge of the purified fluid is realized axially via the inwardlypositioned clean chamber through the outlet A of the housing cover 3(FIG. 1b ). The filter element 4 is secured by axially spaced apartholding and form-fit elements on a housing cover 3 which is attachableto the filter housing 2.

As can be seen in FIG. 1b in connection with FIG. 2, a holding part 7 islocated on an end face of the filter element 4 and is provided inparticular monolithic with an end disk 6 of plastic material that isattached to the end face of the filter medium of the filter element 4.The holding part 7 is designed as a locking hook which is projectingradially past the wall surface of the filter element 4. The holding part7 has correlated therewith a counter holding part 8 which is designed asa locking tab and is arranged on the inner side of the housing cover 3.On the holding part 7 elastic springy contact parts 10 are integrallyformed which in the mounted state press against the counter holding part8 and in this way provide for an increased frictional connection betweenholding part 7 and counter holding part 8. As can be seen in FIG. 2together with FIGS. 3 and 4, on the holding part 7 on the filter element4 two elastic springy contact parts 10 are formed between which thecounter holding part 8 is received. Upon placement of the housing cover3 onto the filter housing 2, a securing rib 16 on the filter housing 2secures the connection against release.

In FIGS. 3 to 5, the filter element 4 is illustrated in differentperspective views. The filter element 4 is hollow-cylindrical and has alongitudinal axis 5. At the end faces, the filter element 4 is framed byan end disk 6 or 9, respectively.

The holding part 7 is embodied monolithic with a first end disk 6 on thefilter element 4 and projects, in particular in radial direction, pastthe outer wall surface of the filter element. In the area of theoppositely positioned end disk 9, there are a total of three form-fitparts 11 uniformly distributed about the circumference which are formedmonolithic with this end disk and, as can be seen in the enlargedillustration according to FIG. 6, are designed pocket-shaped. Eachpocket-shaped form-fit part 11 on the filter element 4 is limited incircumferential direction by a wall while the side of the pocket 11which is positioned opposite the circumferential wall is embodied to beopen. This makes it possible that a complementarily formed counterform-fit part 13 (FIGS. 7, 8) at the inner side of the housing cover 3can move via the open side of the pocket 11 into the latter until ithits the circumferential wall 12.

Accordingly, in the area of both axially oppositely positioned end facesof the filter element 4, holding or form-fit parts 7, 11 are providedwhich, upon rotational movement of the filter element 4 about itslongitudinal axis 5, move into a form-fit connection with the correlatedcounter holding part 8 or counter form-fit part 13 on the housing cover3. In the area of the end disk 6 there is only a single holding part 7while in the area of the oppositely positioned end disk 9 a total ofthree form-fit parts 11 uniformly distributed about the circumferenceare provided. Accordingly, as shown in FIG. 7, on the inner side of thehousing part 3 a total of three counter form-fit parts 13 uniformlydistributed about the circumference are provided also.

The counter form-fit part 13 on the inner side of the housing cover 3,as can be seen in the enlarged illustration according to FIG. 8, isembodied as an axially projecting and circumferentially extendingprojection which is inserted into the pocket 11 with the rotationalmovement upon mounting of the filter element.

As can be seen in FIG. 7 together with FIGS. 9 through 12, on the innerside of the housing cover 3 an elastic springy snap lever 14 is formedwhich in radial direction of the filter element 4 is springy and securesthe mounted filter element 4 in its locked rotational position. On thecircumferential side of the end disk 6 on the filter element 4, there isa locking projection 15 (FIGS. 10, 12) on which the snap lever 14 isresting lockingly when the filter element 4 is closed or locked.Accordingly, in the closed position of the filter element 4 (FIGS. 9,10), the rotational position of the filter element is secured and anaccidental release of the filter element is precluded.

For removal of the filter element 4 from the housing cover 3, the snaplever 14 must be manually moved out of its locked position radiallyoutwardly so that the snap lever 14 is disengaged from the lockingprojection 15 and the locking form fit in circumferential direction iscanceled. Subsequently, the filter element 4 can then be rotated backabout its longitudinal axis until the form-fit part 11 disengages thecounter form-fit part 12 and the holding part 7 also disengages thecounter holding part 8. Subsequently, the filter element 4 can beremoved axially.

The insertion of the filter element 4 into the housing cover 3 isrealized in the reverse sequence wherein the snap lever 14 will lockedautomatically. Accordingly, the filter housing cover 3 and filterelement 4 form a unit that is easy to handle and can be simply joinedwith the filter housing 2 to a filter device 1. Upon installation of theunit of filter housing cover/filter element in the filter housing 2, thehousing-fast securing rib 16 additionally secures the connection ofholding part 7 and counter holding part 8 because, due to theinteraction of holding part 7 and securing rib 16, a rotational movementof the filter element 4 about its longitudinal axis is prevented.

The fixation of the filter element 4 in the air filter is realized inthe illustrated embodiment exclusively in the filter housing cover 3.Accordingly, component tolerances and component movements in operationand component changes due to heat and moisture between filter housing 2and filter housing cover 3 must not be taken into consideration indesigning the attachment and sealing action of the filter element 4.

While specific embodiments of the invention have been shown anddescribed in detail to illustrate the inventive principles, it will beunderstood that the invention may be embodied otherwise withoutdeparting from such principles.

What is claimed is:
 1. A filter device comprising: a filter housing; ahousing cover closing off the filter housing; a filter element disposedin the filter housing; the filter element comprising: a first end diskarranged at an axial end face of the filter element, the first end diskhaving central opening for flow to enter or exit the filter element; asecond end disk arranged on an opposing axial end face of the filterelement and defining a longitudinal axis extending centrally through thecentral opening and the second end disk; a first holding part arrangedon the second end disk and projecting past an outer wall surface of thefilter element; a second holding part in the form of a counter holdingpart arranged on the housing cover and adapted to interact with thefirst holding part, wherein the first holding part and the secondholding part engage each other in a mounted state of the filter elementin the filter device; the filter element comprising a first form-fitpart at an axial spacing to the first holding part and having associatedtherewith a second form-fit part in the form of a counter form-fit part;wherein the first form-fit part and the first holding part, by arotational movement of the filter element about the longitudinal axis ofthe filter element relative to the housing cover results in a) aform-fit engagement of the first holding part with the counter holdingpart; and b) a form-fit engagement of the first form-fit part with thecounter form-fit part; securely mounting the filter element in thefilter device.
 2. The filter device according to claim 1, wherein thefilter element is hollow-cylindrical and the outer wall surface is acylindrical wall surface, wherein the first holding part projectsradially past the cylindrical wall surface.
 3. The filter deviceaccording to claim 2, wherein the first holding part is arranged on thefirst end disk.
 4. The filter device according to claim 3, wherein thefirst form-fit part is arranged on the second end disk of the filterelement.
 5. The filter device according to claim 1, wherein the counterform-fit part and the counter holding part are arranged on the housingcover.
 6. The filter device according to claim 1, wherein several ofsaid first form-fit part are provided and distributed about acircumference of the filter element but axially positioned at a sameheight of the filter element, the several of said first form-fit partformed as a radially outwardly extending projections on the second enddisk; wherein the form fit parts engage corresponding circumferentiallyspaced into counter form-fit parts formed as receiving pockets on thehousing cover into which respective ones of the radially outwardlyextending projections are received when the filter element is rotatedabout the longitudinal axis.
 7. The filter device according to claim 1,wherein the first form-fit part is configured as a bayonet closure. 8.The filter device according to claim 1, further comprising an elasticsnap lever arranged on the housing cover, wherein the filter elementcomprises a locking projection at a circumferential side of the filterelement, wherein the snap lever is resting in the mounted state on thelocking projection.
 9. The filter device according to claim 1, whereinthe first holding part is a locking hook and the counter holding part isprovided on the housing cover and is a locking tab, wherein the lockinghook is a C-shaped locking hook having an opening of the C-shape forreceiving the locking tab, the locking hook having a first springycontact part spaced apart from a second springy contact part, the firstand second spring contact parts arranged at the opening of the C-shapedlocking hook to against engage opposing sides of the counter holdingpart within the C-shaped locking hook.
 10. The filter device accordingto claim 9, wherein the locking hook comprises an elastic springycontact part that loads the locking tab on the housing cover when thefilter element is in the mounted state.
 11. A filter element comprisinga first end disk arranged on axial end face of the filter element, thefirst end disk having central opening; a second end disk arranged on anopposing axial end face of the filter element, defining a longitudinalaxis extending through the first and the second end disk; a holding partarranged on the second end disk and projecting past an outer wallsurface of the filter element and further comprising a form-fit partarranged on the first end disk at an axial spacing relative to theholding part, wherein the filter element is adapted to be inserted intoa filter housing to be closed off by a housing cover, wherein theholding part and the form fit part are configured such that by rotationof the filter element about the longitudinal axis: a) the holding partis configured to engage form-fittingly a counter holding part providedon the housing cover; and b) the form-fit part is configured to engageform-fittingly a counter form-fit part provided on the housing cover.12. The filter element according to claim 11, wherein the holding partis a C-shaped locking hook having an opening of the C-shape forreceiving the counter holding part, the locking hook having a firstspringy contact part spaced apart from a second springy contact part,the first and second spring contact parts arranged at the opening of theC-shaped locking hook to against engage opposing sides of the counterholding part within the C-shaped locking hook.